1. Heat 4- to 6-quart pot over medium-high. When hot, add steak and cook 3 to 5 minutes per side until internal temperature reaches 145°F. Remove steak and keep warm.
2. Add olive oil to same pan; sauté mushrooms and onions until soft. Remove from pan.
3. To make sauce, melt butter in the pot over medium heat. Add garlic and whisk in flour to create a paste; cook 1 minute. Very slowly whisk in half & half, adding a little at a time, and wait to thicken before adding more. When all combined and thickened, stir in Parmesan cheese and 1/2 gorgonzola cheese. Salt and pepper to taste.
4. Toss cooked noodles, mushrooms and onions into the sauce; mix well.
5. Cut steak into thick slices and serve on top of pasta. Sprinkle with remaining gorgonzola and parsley before serving.